THE POLYPODIES. 
117 
The Oak Fern 
{Polypodium Dryopteris). 
This charming little Fern, the fronds of which are thrice 
divided on the plan of an ivy leaf in general outline, is dis- 
tinguished from all others by its peculiarly delicate pale green 
colour, which renders a well-grown clump one of the most 
refreshing and delightful specimens of vegetable life which 
the eye could desire to rest upon. The fronds stand generally 
Fig. 25.— Polypodium Dryopteris. 
about Gin. to 7in. high, but are an inch or two longer, the 
tall, slender, green stalks bending back at an abrupt angle, 
just where the leafy portion commences, so that the latter 
lies nearly horizontally. This bend is another distinctive 
mark, and is useful in discriminating it from the Limestone 
Polypody next described, and which otherwise closely resembles 
it, though lacking the special tint of green. The young fronds 
also, when unfolding, exactly resemble the pawnbroker’s sign 
